We have continued our studies of the determinants of cardiac disease in alcoholic patients by analyzing the incidence of preclinical cardiomyopathy in chronic alcoholics. Noninvasive systolic time intervals were measured in 22 males and 14 females of similar age, duration of alcoholism and degree of cirrhosis. Males had a 30% prolongation of the systolic time interval ratio whereas females were entirely normal, indicating that sex is one determinant of cardiomyopathy. Hemodynamic characteristics of the progression of alcoholic cardiomyopathy were examined in 24 patients. Deterioration of cardiac function progressed from isolated contractile deficit to stages characterized successively by impaired pump performance, followed by cardiomegaly, symptomagology and decompensation with pulmonary congestion. Animals consuming 36% of calories as ethanol up to 2 years without evident malnutrition were observed to have prolonged H-V and ORS conduction associated with dilatation of the intercalated disc on E-M. A similar group of animals were also tested for ventricular electrical instability during a 2 hr ethanol infusion with maximal blood levels of 140 mg%. Ventricular responses were tested at 15 min. intervals using electrical stimuli up to 50 ma. Ethanol infusion in nonalcoholic animals was associated with a slight decrease in threshold with tachycardia. The chronic EtOH animals exhibited a substantial reduction of threshold to 15 ma associated with ventricular fibrillation without changes in blood substrates or electrolytes. Eighteen chronic alcohol patients without heart failure or hypertrophy presented with supraventricular or ventricular tachycardia and normal blood chemistries. At recovery they had normal heart size but prolonged conduction times in the atrium and ventricle and abnormal systolic time intervals. Since the arrhythmias did not occur in the absence of ethanolism and frequently disappeared spontaneously as blood levels declined, mild conduction abnormalities intensified by acute ethanol use may precipitate arrhythmias. BIBLIOGRAPHIC REFERENCES: Ettinger PO, Lyons M, Oldewurtel HA, and Regan TJ: Cardiac conduction abnormalities produced by chronic alcoholism. Am Heart J 91: 66-78, 1976. Wu CF, Sudhakar M, Jaferi G., Ahmed SS, and Regan TJ: Preclinical cardiomyopathy in chronic alcoholics: A sex difference. Am Heart J 91: 281-286, 1976.